Cylinder lock

Abstract: When a key other than a regular key or the like is inserted to forcibly rotate a key rotor, a coupling member is moved in a direction indicated by an arrow by an uncoupling mechanism. This movement uncouples a rear rotor from the coupling member. As a result, the key rotor and a sleeve only rotate idly, and the rear rotor and a lock lever are not rotated. Hence, a cylinder lock is not unlocked, and no damaging force is never applied to components of the cylinder lock such as tumblers.

Description: The invention relates to cylinder locks designed to prohibit wrongful unlocking and in particular to a cylinder lock according to the preamble of each of claims 1 to 4. Related art A cylinder lock arranged on a door of an automobile is designed as follows. A plurality of tumblers are arranged so as to be movable in radial directions in a key rotor that is rotatably arranged in a rotor case, and such plurality of tumblers are urged by springs in a single direction. As the rotation of the key rotor is blocked with end portions of the tumblers engaged with tumbler engagement grooves arranged in inner circumferential portions while inserted thereinto, the cylinder lock can be locked. To unlock the cylinder lock, a regular key is inserted into a keyhole of the key rotor. As a result, the respective tumblers are moved so as to be released from the tumbler engagement grooves by the key. As the key is rotated, the key rotor is rotated, which causes the lock lever to rotate and hence unlocks the cylinder lock. In the cylinder lock of this type when a key other than the regular key, a screwdriver, or the like is inserted into the keyhole of the key rotor to forcibly rotate the key rotor, the end portions of the tumblers are forcibly biased onto the tumbler engagement grooves of the rotor case, which in turn breaks either the tumblers or the rotor case. As a result, the cylinder lock is no longer used again. By the way it is conceivable to improve the strength of the respective components of the cylinder lock. However, this requires that the thicknesses of the components be increased, which in turn imposes the problem of increasing the size of the cylinder lock as a whole. Another way to prohibit wrongful unlocking is presented by the European Patent Application 0571 249 A1. Said prior art document discloses a tumbler-lock with a rotor turnably arranged in an intermediate sleeve, said sleeve being on its part rotatably provided in a fixedly arranged housing. The rotor is provided with radially movable tumblers, such as plates or pistons, said tumblers interlocking the rotor with said intermediate sleeve when no key is inserted. An intermediate plate is slidably received in the sleeve and is provided to rotate integrally with the sleeve. A retaining member is slidably received in a cap member to rotate integrally with said cap member. The retaining member and intermediate plate are spring biased and kept at their relative position to each other by a protrusion groove combination. In the case where a wrong key is inserted, the rotor rotates integrally with the sleeve since said tumblers are not unlocked and the retaining member remains out of engagement with the housing. Thus, since the key rotor is now separated from the lock lever, any force applied to the key rotor by a wrong key simply results in turning the rotor but not in damaging the tumblers. Although the key lock known from EP-A-0 571 249 shows a coupling device which consists of an intermediate plate and a retaining member, both these components are complex in shape and require close dimensioning, so that their manufacture is costly and their assembly complicated. Accordingly, it is an objective of the present invention to improve a cylinder lock as indicated above such as to prohibit wrongful unlocking in a way that it can be used again after forceful opening with the wrong key by allowing no damaging forces to be applied to the components of said cylinder lock, presenting a structure which permits a simple mounting process and components that are to be manufactured at low costs. According to the present invention, this objective is performed by the features of each of the claims 1 to 4. In the cylinder lock according to the present invention, the tumblers are made engageable with the sleeve in the rotational direction with ends thereof held while inserted into the tumbler engagement grooves by the spring members before a key is inserted. Therefore, under this condition, the key rotor and the sleeve are rotatable integrally with each other. In addition, the key rotor side coupling portion is coupled with the rear rotor side coupling portion by the coupling member. Therefore, the key rotor and he rear rotor are rotatable integrally with each other. When the regular key is inserted into the keyhole under this pre-insertion condition, the tumblers are moved and thereby released from the tumbler engagement grooves. As a result, the key rotor is made freely rotatable with respect to the sleeve. Therefore, as the inserted key is rotated, the key rotor rotates, but the sleeve does not rotate. Since the sleeve does not rotate, the coupling member is not moved to the disengagement position; i.e., the key rotor and the rear rotor remain coupled with each other. As the key rotor is rotated, the rear rotor and hence the lock lever are rotated, so that the cylinder lock is unlocked. Further, if a key other than the regular key, a screwdriver, or the like is inserted into the keyhole of the key rotor to forcible rotate the key rotor under the aforementioned pre-insertion condition, then the key rotor and the sleeve are rotated integrally with each other since the tumblers are left inserted into the tumbler engagement grooves. However, the rotation of the sleeve causes the moving element of the uncoupling mechanism to move in the radial direction, and such movement of the moving element causes the coupling member to move to the disengagement position, which in turn uncouples the key rotor from the rear rotor, making the key rotor freely rotatable. As a result, the key rotor and the sleeve rotate integrally with each other, but the rear rotor and hence the lock lever do not rotate, so that the cylinder key cannot be unlocked. In other words, even if the key rotor is forcibly rotated by the wrong key or the like, the key rotor and the sleeve only rotate idly. Therefore, not only the cylinder lock is not unlocked, but also no damaging force is applied to the components of the cylinder lock, which excludes the possibility of the components being broken and hence allows the cylinder lock to be used again. In the cylinder lock according to the present invention, the tumblers are made engageable with the sleeve in the rotational direction with the ends thereof held while inserted into the tumbler engagement grooves by the spring members under the pre-insertion condition, in a manner similar to the aforementioned case. Therefore, under this condition, the key rotor and the sleeve are rotatable integrally with each other. In addition, the moving member is set to the coupling position and the lock lever is set to the engagement position so that the lock lever is engaged with the key rotor. Therefore, the key rotor and the lock lever are rotatable integrally with each other. When the regular key is inserted into the keyhole under this pre-insertion condition, the tumblers are moved and thereby released from the tumbler engagement grooves. As a result, the key rotor is made freely rotatable with respect to the sleeve. Therefore, as the inserted regular key is rotated, the key rotor is rotated with respect to the sleeve, which rotates the lock lever engaged with the key rotor integrally, so that the cylinder lock can be unlocked. Since the sleeve does not rotate at this instance, the moving member remains held in the coupling position. Further, if a key other than the regular key, a screwdriver, or the like is inserted into the keyhole to forcible rotate the key rotor under the aforementioned pre-insertion condition, then the key rotor and the sleeve are rotated integrally with each other with the tumblers being brought into engagement with the tumbler engagement grooves. However, the rotation of the sleeve causes the moving member to move to the uncoupling position by the cam portion arranged in the sleeve and, in association therewith, the lock lever is moved to the disengagement position, so that the lock lever is disengaged from the key rotor. Therefore, the key rotor and the sleeve rotate integrally with each other, but the lock lever does not rotate, thus not allowing the cylinder key to be unlocked. In this case also, even if the key rotor is forcibly rotated by the wrong key or the like, the key rotor and the sleeve only rotate idly. Therefore, not only the cylinder lock is not unlocked, but also no damaging force is applied to the components of the cylinder lock, which excludes the possibility of the components being broken and hence allows the cylinder lock to be used again. In the cylinder lock according to the present invention, the tumblers are made engageable with the sleeve in the rotational direction with the ends thereof held while inserted into the tumbler engagement grooves by the spring members under the pre-insertion condition, in a manner similar to the aforementioned cases. Therefore, under this condition, the key rotor and the sleeve are rotatable integrally with each other. In addition, the rear rotor is set to the uncoupling position and the lock lever is set to the disengagement position. Therefore, the lock lever is disengaged from the key rotor. When the regular key is inserted into the keyhole under this pre-insertion condition, the tumblers are moved and thereby released from the tumbler engagement grooves. As a result, the key rotor is made freely rotatable with respect to the sleeve. As the inserted regular key is rotated, the key rotor is rotated with respect to the sleeve, which rotates the rear rotor integrally with the key rotor. Then, the rear rotor, while being rotated, is moved to the coupling position by the cam portion arranged in the sleeve and, in association therewith, the lock lever is moved to the engagement position to be engaged with the rear rotor. Therefore, the key rotor and the lock lever are rotated integrally with each other, so that the cylinder lock can be unlocked. Further, if a key other than the regular key, a screwdriver, or the like is inserted into the keyhole to forcible rotate the key rotor under the aforementioned pre-insertion condition, then the key rotor and the sleeve are rotated integrally with each other with the tumblers being brought into engagement with the tumbler engagement grooves. When the sleeve and the rear rotor are rotated integrally with each other, the rear rotor is held in the disengagement position and the lock lever remains set to the disengagement position since the positional relationship between the sleeve and the rear rotor remains unchanged. Therefore, the key rotor, the sleeve, and the rear rotor rotate integrally with one another, but the lock lever is not rotated, not allowing the cylinder lock to be unlocked. In this case also, even if the key rotor is forcibly rotated by the wrong key or the like, the key rotor, the sleeve, and the rear rotor only rotate idly. Therefore, not only the cylinder lock is not unlocked, but also no damaging force is applied to the components of the cylinder lock, which excludes the possibility of the components being broken and hence allows the cylinder lock to be used again. In the cylinder lock according to the present invention, the tumblers are made engageable with the sleeve in the rotational direction with the ends thereof held while inserted into the tumbler engagement grooves by the spring members under the pre-insertion condition, in a manner similar to the aforementioned cases. Therefore, under this condition, the key rotor and the sleeve are rotatable integrally with each other. In addition, the moving member is set to the coupling position and the coupling member is set to the engagement position, so that the key rotor is engaged with the lock lever through the coupling member. Hence, the key rotor and the lock lever are rotatable integrally with each other. When the regular key is inserted into the keyhole under this pre-insertion condition, the tumblers are moved and thereby released from the tumbler engagement grooves. As a result, the key rotor is made freely rotatable with respect to the sleeve. Therefore, as the inserted regular key is rotated, the key rotor is rotated with respect to the sleeve, which causes the lock lever engaged with the key rotor through the coupling member to be rotated integrally with the key rotor, so that the cylinder lock can be unlocked. Since the sleeve does not rotate at this instance, the moving member remains held in the coupling position. Further, if a key other than the regular key, a screwdriver, or the like is inserted into the keyhole to forcible rotate the key rotor under the aforementioned pre-insertion condition, then the key rotor and the sleeve are rotated integrally with each other with the tumblers being brought into engagement with the tumbler engagement grooves. However, when the sleeve is rotated, the moving member is moved to the uncoupling position by the cam portion arranged in the sleeve and, in association therewith, the coupling member is moved to the disengagement position, thus disengaging the key rotor from the lock lever. Therefore, the key rotor and the sleeve rotate integrally with each other, but the coupling member and the lock lever do not rotate, so that the cylinder lock cannot be unlocked. In this case also, even if the key rotor is forcibly rotated by the wrong key or the like, the key rotor and the sleeve rotate only loosely. Therefore, not only the cylinder lock is not unlocked, but also no damaging force is applied to the components of the cylinder lock, which excludes the possibility of the components being broken and hence allows the cylinder lock to be used again. In the cylinder lock according to the present invention, the moving block is engaged with the sleeve and the rotor case so as to bridge between the sleeve and the rotor case while brought into engagement with the original position engagement recess of the rotor case before a key is inserted as well as when the regular key is inserted and rotated. This engagement of the moving block with the sleeve and the rotor case holds the sleeve in the original position. On the other hand, if a key other than the regular key, a screwdriver, or the like is inserted to forcibly rotate the key rotor, then the moving block moves toward the key rotor to be engaged with the engagement recess in the key rotor in association with the rotation of the sleeve, which in turn engages the moving block with the sleeve and the key rotor so as to bridge between the sleeve and the key rotor. As a result, the sleeve and the key rotor rotate integrally with each other. When the sleeve and the key rotor are returned to the original position, the moving block is moved so as to be engaged with the original position engagement recess of the rotor case, so that the moving block is engaged with the sleeve and the rotor case while bridging between the sleeve and the rotor case. The engagement of the moving block with the sleeve and the rotor case causes the sleeve to be held in the original position. Therefore, the original position of the sleeve and the key rotor can be identified. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a longitudinal sectional side view showing a first embodiment of the invention; Fig. 2 is a sectional view taken along a line S1-S1 in Fig. 1; Fig. 3 is a partially sectional view taken along a line S2-S2 in Fig. 1; Fig. 4 is a sectional view taken along a line S3-S3 in Fig. 1; Fig. 5 is a cutaway perspective view of a rear rotor side coupling portion; Fig. 6 is an exploded perspective view.; Fig. 7 is a view equivalent to Fig. 2 with a regular key inserted; Fig. 8 is a rear view; Fig. 9 is a view equivalent to Fig. 1 with a key rotor forcibly rotated by a wrong key or the like; Fig. 10 is a sectional view taken along a line S4-S4 in Fig. 9; Fig. 11 is a longitudinal sectional side view of a second embodiment of the invention with a regular key inserted; Fig. 12 is a rear view of the second embodiment of the present invention; Fig. 13 is a sectional view taken along a line T1-T1 in Fig. 11; Fig. 14 is a sectional view taken along a line T2-T2 in Fig. 11; Fig. 15 is a sectional view taken along a line T3-T3 in Fig. 11; Fig. 16 is a sectional view taken along a line T4-T4 in Fig. 15; Fig. 17 is a longitudinal sectional side view of a rotor case; Fig. 18 is a rear view of the rotor case; Fig. 19 is a perspective view of a key rotor; Fig. 20 is a perspective view of a sleeve; Fig. 21 is a perspective view of a moving member; Fig. 22 is a perspective view of a moving block; Fig. 23 is a view equivalent to Fig. 11 with the key rotor forcibly rotated with a wrong key or the like; Fig. 24 is a rear view; Fig. 25 is a sectional view taken along a line T5-T5 in Fig. 23; Fig. 26 is a sectional view taken along a line T6-T6 in Fig. 23; Fig. 27 is a sectional view taken along a line T7-T7 in Fig. 23; Fig. 28 is a longitudinal sectional side view of a third embodiment of the invention before a key is inserted; Fig. 29 is a longitudinal sectional side view of a portion different from that shown in Fig. 28; Fig. 30 is a sectional view taken along a line U1-U1 in Fig. 28; Fig. 31 is a sectional view taken along a line U2-U2 in Fig. 28; Fig. 32 is a rear view of the rear rotor; Fig. 33 is a partial bottom view as viewed from a direction indicated by an arrow U3 shown in Fig. 28; Fig. 34 is a sectional view taken along a line U4-U4 in Fig. 29; Fig. 35 is a view equivalent to Fig. 28 with the cylinder lock being opened by inserting a regular key; Fig. 36 is a sectional view taken along a line U5-U5 in Fig. 35; Fig. 37 is a view equivalent to Fig. 34 with the moving block engaged with the sleeve and the key rotor; Fig. 38 is a longitudinal sectional side view of a fourth embodiment of the invention with a regular key inserted; Fig. 39 is a rear view of the fourth embodiment of the present invention; Fig. 40 is a sectional view taken along a line V1-V1 in Fig. 38; Fig. 41 is a sectional view taken along a line V2-V2 in Fig. 38; Fig. 42 is an exploded perspective view of a main portion; Fig. 43 is a view equivalent to Fig. 38 with the key rotor forcibly rotated by a wrong key or the like; Fig. 44 is a rear view; Fig. 45 is a sectional view taken along a line V3-V3 in Fig. 43; and Fig. 46 is a sectional view taken along a line V4-V4 in Fig. 43. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First embodiment A cylinder lock, which is a first embodiment of the invention, will now be described with reference to Figs. 1 to 10. Fig. 1 shows a condition before a key is inserted; Fig. 6 shows the components in exploded form; and Fig. 9 shows a condition in which a key rotor is forcibly rotated by a wrong key or the like. Referring first to Fig. 1 and Figs. 2 to 5 and Fig. 6 which are related to Fig. 1, the cylinder lock, which is the first embodiment, will be described. A rotor case 1 is formed into a substantially cylindrical member by coupling a cap portion 2 with a case main body 3 in an axial direction (the right side as viewed in Fig. 1 is referred to as the front side). On an upper portion of the case main body 3 is a moving element setting groove 4, and a spring holding plate 5 is arranged on an upper portion of the groove 4. In a rear portion of the case main body 3 are retaining portions 6, 6 as well as a spring stopper portion as shown in Fig. 6. A substantially cylindrical sleeve 8 is rotatably arranged inside the rotor case 1. As shown in Fig. 2, tumbler engagement grooves 9, 9 are formed on the inner surface of the sleeve 8, and a recessed cam portion 11 is formed on the outer surface thereof. The cam portion 11 constitutes a part of an uncoupling mechanism 10, which will be described later. In addition, a collar portion 12 that is opened at the cam portion 11 is formed at the rear end of the sleeve 8. A substantially shaft-like key rotor 13 is rotatably arranged inside the sleeve 8. A keyhole 14 runs through the key rotor 13 in the axial direction, and a plurality of tumbler setting grooves 15 are arranged in the key rotor 13 in the radial direction. Tumblers 16 are movably set in the respective tumbler setting grooves 15. Each tumbler 16 is urged so as to move in a direction indicated by an arrow A1 in Fig. 2 by a corresponding spring member 17, with an end portion 16a thereof being held while inserted into one of the tumbler engagement grooves 9, 9. As a result of the construction, the tumblers can be engaged with the sleeve 8 in a direction of rotation. It should be noted that each tumbler 16 is designed to be disengaged from the tumbler engagement groove 9 by being moved in a direction opposite to the arrow A1 upon insertion of a key (regular key) into the keyhole 14 (see Fig. 7). Further, a support shaft portion 18 is formed from the intermediate portion toward the rear portion of the key rotor 13. A recessed key rotor side coupling portion 19 is formed in a stepped portion of the intermediate portion. On the support shaft portion 18 a rear rotor 20 is rotatably fitted into the key rotor 13 so as to confront each other in the axial direction. As shown in Fig. 5, a recessed rear rotor side coupling portion 21 is formed on the rear rotor 20, and a release portion 22, which is an annular slit that is opened at both wall surfaces of the rear rotor side coupling portion 21, is also formed. In addition, a lever fitting protuberance 23 is arranged at the rear end of the rear rotor 20. A lock lever 24 is fitted into and coupled with this lever fitting protuberance 23. The lock lever 24 has not only a positioning portion 25 but also a coupling portion 24a that is coupled with, e.g., a door lock mechanism. The lock lever 24 and hence the key rotor 13 are designed to be held in a predetermined angular position by a torsion spring 26. That is, as shown in Fig. 8, with the positioning portion 25 of the lock lever 24 and the spring hold plate 7 of the case main body 3 being aligned, the torsion spring 26 is squeezed in to cause both ends 26a, 26a of the torsion spring 26 to be retained by both sides of the positioning portion 25 and the spring hold plate 7. The lock lever 24 is made unreleasable by an E ring 18a attached to an end portion of the support shaft portion 18. By the way, the uncoupling mechanism 10 is constructed in the following manner. A moving element 27 is set in the moving element setting groove 4 so as to be movable in the radial directions (up and down). A projected fitting portion 27a that is fitted into the cam portion 11 is formed on the lower surface of the moving element 27. This moving element 27 is urged by springs 28 in such a direction as to be fitted into the cam portion 11. The moving element 27 is designed to move in a direction indicated by an arrow A2 in Figs. 1 and 2 upon rotation of the sleeve 8. A support piece 29 is formed in the rear of the moving element 27. The support piece 29 is an arc subtending the center of the key rotor 13. Further, an intermediate block 30 is disposed on the rear rotor side coupling portion 21 so as to be movable in both radial and rotational directions. A holding groove 31 is formed in an upper portion of the intermediate block 30. The holding groove 31 retains the support piece 29 in the radial direction and allows the support piece 29 to move in the rotational direction. In both lower and front portions of the intermediate block 30 are a coupling member holding recess 32 and a coupling member holding projection 33, respectively. On the other hand, a coupling member 34 whose movement is controlled by the uncoupling mechanism 10 is arranged so as to be movable in the radial directions while bridging between the key rotor side coupling portion 19 and the rear rotor side coupling portion 21. That is, the coupling member 34 is substantially C-shaped with an arcuate upper piece 35 and an arcuate lower piece 36 coupled through an intermediate portion 37. The intermediate portion 37 is fitted with the key rotor side coupling portion 19, and the upper piece 35 and the lower piece 36 are fitted into the coupling member holding projection 33 and the coupling member holding recess 32 of the intermediate block 30 within the rear rotor side coupling portion 21, respectively. Under the conditions shown in Figs. 1 and 2, the lower piece 36 of the coupling member 34 confronts both wall surfaces of the rear rotor side coupling portion 21 in the rotational direction and does not confront the release portion 22, so that the coupling member 34 is so positioned as to be engageable with the respective coupling portions 19, 21 in the rotational direction. Further, under the condition shown in Fig. 9, the lower piece 36 of the coupling member 34 confronts the release portion 22 in the rotational direction in the rear rotor side coupling portion 21. That is, the lower piece 36 is disengaged, so that the key rotor 13 is in such a release position as to be freely rotatable independently of the rear rotor 20. A mode of operation of the aforementioned construction will be described next. As shown in Figs. 1 to 4, the respective tumblers 16 are engageable in the rotational direction with the sleeve 8 while held with the end portions 16a thereof inserted into the tumbler engagement groove 9 by the corresponding spring members 17 before the key is inserted. Therefore, under this condition, the key rotor 13 is rotatable integrally with the sleeve 8. Further, the key rotor side coupling portion 19 is ready to be coupled with the rear rotor side coupling portion 21 through the coupling member 34. Therefore, the key rotor 13 is rotatable integrally with the rear rotor 20. When a regular key is inserted into the keyhole 14 under this pre-insertion condition, the ends 16a of the respective tumblers 16 move to be released from the tumbler engagement groove 9 as shown in Fig. 7. As a result, the key rotor 13 is freely rotatable with respect to the sleeve 8. Therefore, as the inserted key is rotated, the key rotor 13 rotates, whereas the sleeve 8 does not rotate. With the sleeve 8 not rotating, the moving element 27 of the uncoupling mechanism 10 is not moved in the radial direction (in the direction indicated by the arrow A2 in Figs. 1, 2, and 7). That is, the coupling member 34 does not move to the uncoupling position, thus leaving the key rotor 13 and the rear rotor 20 coupled. As the key rotor 13 rotates, so do the rear rotor 20 and hence the lock lever 24, which in turn unlocks the cylinder lock. It should be noted that when the rotating force applied to the key is removed, the spring force of the torsion spring 26 causes the rear rotor 20 and the key rotor 13 to return to the original positions thereof. Further, when a key other than the regular key, a screwdriver, or the like is inserted into the keyhole 14 in the key rotor 13 to rotate the key rotor 13 forcibly under the aforementioned pre-insertion condition, the key rotor 13 rotates integrally with the sleeve 8 because the respective tumblers 16 are left inserted into the tumbler engagement groove 9. However, the rotation of the sleeve 8 causes the moving element 27 of the uncoupling mechanism 10 to move in the radial direction (in the direction indicated by the arrow A2) along the slopes of the cam portion 11. This movement, in turn, causes the coupling member 34 to move to the uncoupling position shown in Figs. 9 and 10 (the position raised in the direction of the arrow A2), so that the lower piece 36 of the coupling member 34 confronts the release portion 22 and, as a result, the coupling member 34 is uncoupled from the rear rotor 20, allowing the key rotor 13 to be freely rotatable. Therefore, if the key rotor 13 is continuously rotated, the lower piece 36 of the coupling member 34 is inserted into the release portion 22, allowing the key rotor 13 to rotate. However, the rear rotor 20 and hence the lock lever 24 do not rotate, which does not allow the cylinder lock to be unlocked. That is, even if the key rotor 13 is rotated by a wrong key or the like, the key rotor 13, the sleeve 8, and the coupling member 34 only rotate idly, thereby not allowing the cylinder lock to be unlocked nor giving any damaging force to the respective components thereof. As a result, not only the possibility of the components being broken is excluded, but also the cylinder lock can be used again. It should be noted that if the lock lever 24 is rotated wrongfully, the rear rotor 20 and the key rotor 13 rotate slightly, and the sleeve 8 also rotates slightly, thereby causing the moving element 27 to move in the direction of the arrow A2. As a result, the intermediate block 30 moves, which in turn causes a part 30a (see Fig. 6) of the intermediate block 30 to be abutted against either one of the retaining portions 6, 6 (see also Fig. 6) of the case main body 3. Hence, the rotation of the lock lever 24 is blocked, thereby not allowing the cylinder lock to be unlocked. According to the cylinder lock, which is the first embodiment, the key rotor 13, the sleeve 8, and the coupling member 34 only rotate idly although the key rotor is forcibly rotated by a key other than the regular key, a screwdriver, or the like. Therefore, not only the cylinder lock cannot be unlocked, but also no damaging force is applied to the components thereof such as the tumblers 16, the key rotor 13, and the sleeve 8, excluding the likelihood of these components being broken and thereby ensuring reuse of the cylinder lock. Second embodiment A cylinder lock, which is a second embodiment of the invention, will be described next with reference to Figs. 11 to 27. Figs. 11 to 16 show conditions with a key 41 being inserted; Figs. 17 to 22 show the components; and Figs. 23 to 27 show conditions with the key rotor being forcibly rotated by a wrong key or the like. Referring first to Figs. 11 to 18, a rotor case 42 is cylindrical, and a moving member setting groove 43 is formed in an upper portion of the rotor case 42. A spring hold plate 44 is attached to the upper portion of the moving member setting groove 43. Further, an arcuate groove 45 is formed in the rear of the rotor case 42 (on the right side as viewed in Figs. 11 and 17) with retaining portions 45a, 45a formed on both sides of the groove 45. Still further, a sloped V-shaped original position engagement recess 46 is formed in a position about 90° shifted in a circumferential direction with respect to the moving member setting groove 43. A substantially cylindrical sleeve 47 is arranged in an intermediate portion inside the rotor case 42, the portion being intermediate as viewed in the axial direction. Tumbler engagement grooves 48, 48 are formed on the inner surface of the sleeve 47 so as to confront each other, and as shown in Fig. 20, not only a recessed cam portion 49 is formed on the outer surface thereof, but also a moving block setting hole 50 is formed in a position about 90° shifted in the circumferential direction with respect to the cam portion 49 so as to pass through in the radial direction. A key rotor 51 is rotatably arranged inside the sleeve 47. The key rotor 51 is provided with a cover 52 so as not to be released frontward with respect to the rotor case 42. The key rotor 51 has an axially extending keyhole 53 and a plurality of radially extending tumbler setting grooves 54, 55. In this case, the front side portions of the tumbler setting grooves 54, 55 are different in shape from the rear side portions thereof. Two types of tumblers 56, 57 are set in these tumbler setting grooves 54, 55 so as to be movable in the radial directions. The respective tumblers 56, 57 are urged in a single direction by corresponding spring members 58. The respective tumblers 56, 57 have ends thereof projected from the tumbler setting grooves 54, 55 and inserted into the tumbler engagement groove 48 of the sleeve 47 (see Figs. 25 and 26), making the respective tumblers 56, 57 engageable with the sleeve 47 in the rotational direction. As the regular key 41 is inserted into the keyhole 53, the respective tumblers 56, 57 are moved in such a direction as to be set in the tumbler setting grooves 54, 55, thereby being released from the tumbler engagement groove 48 (see Figs. 13 and 14). Further, a shaft portion 59 is projected from the rear of the key rotor 51. A lock lever engagement recess 60 is formed on top of the root of the shaft portion 59 as shown also in Fig. 19. Still further, an engagement recess 61 is formed on the outer surface on the rear side of the key rotor 51 so as to confront the original position engagement recess 46. A moving member 62 shown in Fig. 21 is arranged in the moving member setting groove 43 of the rotor case 42 so as to be movable in a circumferential direction (up and down as viewed in Fig. 11). The moving member 62 is urged toward the sleeve 47 by a spring member 63 that is interposed between the moving member 62 and the spring hold plate 44 with a fitting portion 62a thereof fitted into the cam portion 49 on the sleeve side 47, and is arranged so as to bridge between the rotor case 42 and the sleeve 47. On the rear side of the moving member 62 is a retaining groove 64 that has openings on the rear as well as on both left and right sides (see Fig. 15). The moving member 62 is movable in the radial directions between a coupling position at which the fitting portion 62a is fitted into the cam portion 49 (see Figs. 11, 14, and 15) and an uncoupling position at which the fitting portion 62a comes out of the cam portion 49 as a result of the rotation of the sleeve 47 (see Figs. 23, 26, and 27). A lock lever 65 is attached to the shaft portion 59 of the key rotor 51 so as to be unreleasable by an E ring 66. In the lock lever 65 a fitting hole 67 into which the shaft portion 59 is fitted is elongated in a single radial direction, and a projection 68 engageable with the lock lever engagement recess 60 on the shaft portion 59 side is formed on a part of the fitting hole 67. Further, a retaining projection 69 that is retained in the retaining groove 64 of the moving member 62 is arranged integrally with the lock lever 65. The lock lever 65 is movable in the radial directions between an engagement position at which the projection 68 is engaged with the lock lever engagement recess 60 as shown in Figs. 11 and 12 and a disengagement position at which the projection 68 is disengaged from the lock lever engagement recess 60 as shown in Figs. 23 and 24. The lock lever 65 is rotatable integrally with the key rotor 51 with the projection 68 engaged with the lock lever engagement recess 60. A return spring 70, which is a torsion spring, is provided in an outer circumferential portion in the rear of the key rotor 51. This return spring 70 gives a force for urging the lock lever 65 and the key rotor 51 to an original position when the lock lever 65 and the key rotor 51 are rotated from the original position. A moving block 71 shown in Fig. 22 is movably arranged in the moving block setting hole 50 of the sleeve 47. This moving block 71 is urged toward the rotor case 42 by a spring member 72, and holds the sleeve 47 in the original position with a first engagement portion 73 thereof engaged with the original position engagement recess 46 (see Figs. 14 to 16). This moving block 71 has a second engagement portion 74 on the key rotor 51 side. It should be noted that reference numeral 75 in Figs. 23, 25 to 27 denotes a wrong key as a key other than the regular key. A mode of operation of the aforementioned construction will be described next. In the condition before the key is inserted, the ends of the respective tumblers 56, 57 are inserted into the tumbler engagement grooves 48, 48 of the sleeve 47 by the spring members 58. That is, the respective tumblers 56, 57 are readily engageable with the sleeve 47 in the rotational direction (see Figs. 25 and 26). Therefore, under this condition, the key rotor 51 and the sleeve 47 are rotatable integrally with each other. In addition, not only the moving member 62 is set to the coupling position, but also the lock lever 65 is set to the engagement position, so that the projection 68 of the lock lever 65 is engaged with the lock lever engagement recess 60 of the key rotor 51 (see Figs. 11 and 12). Therefore, the key rotor 51 and the lock lever 65 are rotatable integrally with each other. At this instance, the engagement groove 64 of the moving member 62 is in communication with the groove 45 of the rotor case 42 (see Fig. 15). In addition, the moving block 71 bridges between the sleeve 47 and the rotor case 42 while engaged with the original position engagement recess 46 of the rotor case 42. As a result of the engagement, the sleeve 47 is held in the original position. When the regular key 41 is inserted into the keyhole 53 under this condition, the respective tumblers 56, 57 are released from the tumbler engagement grooves 48, 48 and set in the tumbler setting grooves 54, 55 (see Figs. 13 and 14). As a result, the key rotor 51 is made freely rotatable with respect to the sleeve 47. Hence, as the inserted regular key 41 is rotated, the key rotor 51 is rotated with respect to the sleeve 47 and hence the rotor case 42, which in turn rotates the lock lever 65 that is engaged with the key rotor 51 integrally, thereby allowing the cylinder lock to be unlocked. At this instance, the range of rotation of the key rotor 51 and the lock lever 65 is regulated by the retaining portions 45a, 45a of the rotor case 42. That is, the key rotor 51 and the lock lever 65 can rotate within the range of about 65° from the original position in both left and right directions. In addition, since the sleeve 47 does not rotate even if the key rotor 51 and the lock lever 65 are rotated within such range, the moving member 62 remains held in the coupling position. Further, if a key other than the regular key, e.g., a wrong key 75, is inserted into the keyhole 53 to forcibly rotate the key rotor 51 under the aforementioned pre-insertion condition, at least some of the tumblers 56, 57 are engaged with the tumbler engagement groove 48. As a result, the key rotor 51 and the sleeve 47 are rotated integrally with each other (see Figs. 25 to 27). When the sleeve 47 is rotated, the moving member 62 is caused to move to the uncoupling position, which is up, by the slopes of the cam portion 49 arranged in the sleeve 47 (see an arrow B1 in Figs. 23 and 26) and, in association therewith, the lock lever 65 is moved to the disengagement position, which is up (see the arrow B1 in Fig. 24), disengaging the projection 68 of the lock lever 65 from the lock lever engagement recess 60 of the key rotor 51. Further, when the sleeve 47 is rotated with respect to the rotor case 42, the moving block 71 is moved toward the key rotor 51 by the slopes of the original position engagement recess 46 (see an arrow B2 in Figs. 26 and 27), which disengages the moving block 71 from the rotor case 42 and in turn engages the moving block 71 with the engagement recess 61 of the key rotor 51. Therefore, in this case, the key rotor 51 and the sleeve 47 are rotated integrally with each other, but the lock lever 65 is not rotated. Thus, the cylinder lock is not unlocked. That is, even if the key rotor is forcibly rotated by the wrong key or the like, the key rotor 51 and the sleeve 47 only rotate idly, which neither unlocks the cylinder lock nor gives any damaging force to the components thereof, thereby excluding the possibility of the components being broken and allowing the cylinder lock to be used again. By the way, when the wrong key 75 is released with the key rotor 51 and the sleeve 47 having been rotated to an arbitrary position from the original position, the key rotor 51 and the sleeve 47 may, in some cases, be out of the original position. In such a case, when the regular key 41 is inserted into the keyhole 53, the respective tumblers 56, 57 are moved to be set in the tumbler setting grooves 54, 55, so that the tumblers 56, 57 are disengaged from the sleeve 47. However, the moving block 71 is engaged so as to bridge between the sleeve 47 and the key rotor 51. Therefore, when the key rotor 51 is rotated by the regular key 41, the sleeve 47 is caused to rotate integrally with the key rotor 51. When the key rotor 51 and the sleeve 47 are rotated as far as to the original position, the first engagement portion 73 of the moving block 71 confronts the original position engagement recess 46 of the rotor case 42 and is thereby engaged therewith (see Figs. 14 and 15). As a result, the key rotor 51 and the sleeve 47 come to be held in the original position. In a manner similar to that of the first embodiment, the cylinder lock according to the second embodiment is provided as only rotating the key rotor 51 and the sleeve 47 idly and not rotating the lock lever 65 when the key rotor 51 is forcibly rotated by the insertion of the wrong key 75 or the like. Therefore, not only the cylinder lock is not unlocked, but also no damaging force is applied to the components thereof. As a result, there is no likelihood that the components will be broken, and the cylinder lock can therefore be used again. The cylinder lock according to the second embodiment is further provided as holding the sleeve 47 in the original position by arranging the moving block 71 in the sleeve 47 and engaging the moving block 71 with the original position engagement recess 46 of the rotor case 42, as well as causing the moving block 71 to be engaged with the key rotor 51 to thereby rotate the sleeve 47 and the key rotor 51 integrally with each other if the sleeve 47 and the key rotor 51 are rotated by the wrong key 75. Therefore, the rotation of the sleeve 47 is prohibited at the time of legally unlocking and locking the cylinder lock. In addition, the original position of the sleeve 47 and the key rotor 51 can be identified. Having no member that moves in the axial direction, the cylinder lock according to the second embodiment is further advantageous in preventing the cylinder lock from becoming large in the axial direction. Third embodiment A cylinder lock, which is a third embodiment of the invention, will be described next with reference to Figs. 28 to 37. Figs. 28 to 34 show conditions before a key is inserted as well as components; Figs. 35 and 36 show conditions with a regular key inserted; and Fig. 37 shows a condition when the key rotor is forcibly rotated by a wrong key or the like. Referring, first, to Figs. 28 to 34, a cylindrical sleeve 82 is rotatably arranged inside a cylindrical rotor case 81. A key rotor 83 is rotatably arranged inside the sleeve 82. The key rotor 83 is provided with a cover 84 so as not to be released frontward. A shaft portion 85 in the rear (on the right portion as viewed in Fig. 28) of the key rotor 83 is projected rearward from a shaft insertion hole 86. The shaft portion 85 is substantially oval in section (see Fig. 31), and has a projection 87 at the rear end thereof. A lock lever engagement recess 88 (see Fig. 30) is formed on the projection 87. Tumbler engagement grooves 89, 89 are formed on the inner surface of the sleeve 82 so as to confront each other. Not only a keyhole (not shown) is formed in the key rotor 83 in the axial direction, but also a plurality of radially extending tumbler setting grooves 91 are formed. The respective tumbler setting grooves 91 have tumblers 92 movably set therein, and the respective tumblers 92 are urged so as to move in a single direction by not shown corresponding springs. A rear rotor 93 is fitted with the shaft portion 85 of the key rotor 83 while positioned inside the rotor case 81. A fitting hole 94 of the rear rotor 93 that is fitted with the shaft portion 85 is elongated in the radial direction (see Figs. 31 and 32), so that the rear rotor 93 rotates integrally with the key rotor 83 and is movable in the radial direction with respect to the key rotor 83. A recess 95 is formed on an upper portion of the rear rotor 93. A cam portion 96 arranged at the rear end portion of the sleeve 82 is fitted into this recess 95. Further, on the rear side of the rear rotor 93 is an arcuate retaining groove 97 (see Fig. 32). A lock lever 98 is engaged with the projection 87 of the key rotor 83 so as to be unreleasable by an E ring 99. A fitting hole 100 of the lock lever 98 that is fitted with the projection 87 is elongated in the radial direction (see Fig. 30). On an upper portion of the fitting hole 100 is a projection 101 engageable with the lock lever engagement recess 88. The projection 101 is formed so as to face downward. On an upper portion of the lock lever 98 is a retaining projection 102 that faces frontward. The front end of the retaining projection 102 is movably inserted into the retaining groove 97 of the rear rotor 93 so as to pass through a hole 103 formed in a rear wall 81a of the rotor case 81. Further, in the lock lever 98 a retaining piece 104 is formed below the fitting hole 100 by cutting a piece and raising the cut piece frontward. This retaining piece 104 is inserted between stopper projections 105, 105 arranged on the rear wall 81a of the rotor case 81 (see Fig. 33). A return spring 106, which is a torsion spring, is arranged around the shaft portion 85 of the key rotor 83. This return spring 106 imparts a force for urging the key rotor 83 and the lock lever 98 to an original position when the key rotor 83 and the lock lever 98 are rotated from the original position. Further, the lock lever 98 is urged upward as viewed in Fig. 28 by this return spring 106. In this case, under the pre-insertion condition, the lock lever 98 is set to a disengagement position, which is up, and the rear rotor 93 engaged with the lock lever 98 is set to an uncoupling position, which is up. Under such condition, the projection 101 of the lock lever 98 is disengaged from the lock lever engagement recess 88 of the key rotor 83 (see Fig. 30). In Figs. 29 and 34 a moving block setting hole 107 is formed in the sleeve 82, and a moving block 108 is set in the moving block setting hole 107 so as to be movable in the radial directions. This moving block 108 is urged toward the rotor case 81 by a pin-like spring member 109 that is arranged so as to pass through the moving block 108. On the rotor case 81 side is an original position engagement recess 111 engageable with a first engagement portion 110 on one side of the moving block 108. On the key rotor 83 side is an engagement recess 113 engageable with a second engagement portion 112 on the other end of the moving block 108. It should be noted that reference numeral 114 in Fig. 35 denotes a regular key. A mode of operation of the aforementioned construction will be described next. Under the condition before the key is inserted, the respective tumblers 92 have the ends thereof inserted into the tumbler engagement groove 89 of the sleeve 82, and therefore are readily engageable with the sleeve 82 in the rotational direction. Therefore, the key rotor 83 and the sleeve 82 are rotatable integrally with each other under this condition. Further, the rear rotor 93 is set to the uncoupling position, and the lock lever 98 is set to the disengagement position, so that the lock lever 98 and the key rotor 93 are readily disengageable from each other. Further, by the moving block 108 being brought into engagement with the original position engagement recess 111 of the rotor case 81, the moving block 108 bridge between the sleeve 82 and the rotor case 81, so that the sleeve 82 is held in the original position by the engagement. When the regular key 114 is inserted into the keyhole of the key rotor 83 under this condition, the respective tumblers 92 are released from the tumbler engagement groove 89 and thereby set in the tumbler setting groove 91. As a result, the key rotor 83 is made freely rotatable with respect to the sleeve 82. As the inserted regular key 114 is rotated, the key rotor 83 is rotated with respect to the sleeve 82, which in turn rotates the rear rotor 93 integrally with the key rotor 83. Then, while being rotated, the rear rotor 93 is caused to move to the coupling position (see Fig. 35), which is down, by the cam portion 96 arranged on the sleeve 82 and, in association therewith, the lock lever 98 is moved to the engagement position (see Figs. 35 and 36), thereby engaging the projection 101 of the lock lever 98 with the lock lever engagement recess 88 of the key rotor 83. Further, in association with the movement of the lock lever 98 to the engagement position, the retaining piece 104 is displaced downward from the stopper projections 105, 105, which in turn allows the lock lever 98 to rotate. As a result, the key rotor 83 and the lock lever 98 are rotated integrally with each other, thus allowing the cylinder lock to be unlocked. At this instance, the range of rotation of the lock lever 98 is regulated by the hole 103 of the rotor case 81. In addition, since the sleeve 82 is held in the original position by the moving block 108 in this case, the sleeve 82 does not rotate although the key rotor 83, the rear rotor 93, and the lock lever 98 are rotated integrally with one another. Further, under the aforementioned pre-insertion condition, a key other than the regular key, e.g., a wrong key (not shown) is inserted into the keyhole to forcibly rotate the key rotor. In this case, at least some of the tumblers 92 are brought into engagement with the tumbler engagement groove 89, so that the key rotor 83, the sleeve 82, and the rear rotor 93 rotate integrally with one another. When the sleeve 82 and the rear rotor 93 rotate integrally, the relative positions of the sleeve 82 and the rear rotor 93 remain unchanged. As a result, the rear rotor 93 remains in the disengagement position, and the lock lever 98 remains in the disengagement position as well. When the sleeve 82 is rotated with respect to the rotor case 81, the moving block 108 is moved toward the key rotor 83 by the slopes of the original position engagement recess 111, which in turn disengages the moving block 108 from the rotor case 81 and engages the moving block 108 with the engagement recess 113 of the key rotor 83 (see Fig. 37). The key rotor 83, the sleeve 82, and the rear rotor 93 rotate integrally with one another, but the lock lever 98 does not rotate in this case, thereby not allowing the cylinder lock to be unlocked. That is, even if the key rotor is forcibly rotated by a wrong key or the like, the key rotor 83, the sleeve 82, and the rear rotor 93 only rotate idly, thereby neither allowing the cylinder lock to be unlocked, nor allowing a damaging force to be applied to the components thereof. Hence, the possibility of the components being broken is excluded, and the cylinder lock can therefore be used again. By the way, when the wrong key is released with the key rotor 83, the sleeve 82, and the rear rotor 93 having been rotated to an arbitrary position from the original position, the key rotor 83, the sleeve 82, and the rear rotor 93 may, in some cases, be out of the original position also in the third embodiment. In such a case, when the regular key 114 is inserted into the keyhole, the respective tumblers 92 are moved so as to be set in the tumbler setting groove 91, so that the tumblers 92 are disengaged from the sleeve 82. However, the moving block 108 is engaged so as to bridge between the sleeve 82 and the key rotor 83. Therefore, when the key rotor 83 is rotated by the regular key 114, the sleeve 82 is rotated integrally with the key rotor 83. When the key rotor 83 and the sleeve 82 are rotated as far as to the original position, the first engagement portion 110 of the moving block 108 confronts the original position engagement recess 111 of the rotor case 81 and thereby is engaged therewith (see Fig. 34). As a result, the key rotor 83 and the sleeve 82 come to be held in the original position. In a manner similar to those of the first and second embodiments, the cylinder lock according to the third embodiment is provided as only rotating the key rotor 83, the sleeve 82, and the rear rotor 93 idly and not rotating the lock lever 98 when the key rotor 83 is forcibly rotated by the insertion of a wrong key or the like. Therefore, not only the cylinder lock is not unlocked, but also no damaging force is applied to the components thereof. As a result, there is no likelihood that the components will be broken, and the cylinder lock can therefore be used again. Further, in a manner similar to that of the second embodiment, the cylinder lock according to the third embodiment is also provided as holding the sleeve 82 in the original position by arranging the moving block 108 in the sleeve 82 and engaging the moving block 108 with the original position engagement recess 111 of the rotor case 81, as well as causing the moving block 108 to be engaged with the key rotor 83 to thereby rotate the sleeve 82 and the key rotor 83 integrally with each other if the sleeve 82 and the key rotor 83 are rotated by a wrong key or the like. Therefore, the rotation of the sleeve 82 is prohibited at the time of legally unlocking and locking the cylinder lock. In addition, the original position of the sleeve 82 and the key rotor 83 can be identified. Having no member that moves in the axial direction, the cylinder lock according to the third embodiment is further advantageous in preventing the cylinder lock from becoming large in the axial direction. Still further, since the retaining piece 104 of the lock lever 98 is interposed between the stopper projections 105, 105 under the pre-insertion condition, the lock lever 98 cannot be rotated even if one tries to rotate the lock lever 98 directly from outside with the cylinder lock locked. Fourth embodiment A cylinder lock, which is a fourth embodiment of the invention, will be described next with reference to Figs. 38 to 46. Since the basic construction of the fourth embodiment is the same as that of the second embodiment, the same components are designated by the same reference characters, and the descriptions thereof will be omitted. Only the different components will be described. Figs. 38 to 41 show conditions before the regular key 41 is inserted; Fig. 42 shows a main portion of major components in exploded perspective form; and Figs. 43 to 46 show conditions in which the key rotor is forcibly rotated by a wrong key or the like. First, in the rotor case 42, the moving member setting groove 43 and the arcuate groove 45 having the retaining portions 45a are formed on a lower portion in the drawings. The recessed original position engagement recess 46 having slopes is formed in a position about 90° shifted in the circumferential direction with respect to the moving member setting groove 43. On the outer surface on the rear side of the key rotor 51 arranged inside the sleeve 47 is the engagement recess 61 as shown in Fig. 42. A coupling member engagement recess 121 is also formed in a position about 90° shifted in the circumferential direction with respect to the engagement recess 61. The moving member setting groove 43 has a moving member 122 arranged so as to be movable in the circumferential direction (up and down as viewed in Fig. 38). The moving member 122 is urged toward the sleeve 47 by the spring member 63 interposed between the moving member 122 and a spring receiving portion 43a. A fitting portion 122a is fitted with the cam portion 49 on the sleeve 47 side. That is, the moving member 122 is arranged so as to bridge between the rotor case 42 and the sleeve 47. On the rear side of the moving member 122 is a retaining groove 123 that is opened on the rear as well as both left and right sides (see Fig. 41). This moving member 122 is designed to be movable in the radial directions between the coupling position at which the fitting portion 122a is fitted into the cam portion 49 (see Figs. 38, 40, and 41) and the uncoupling position at which the fitting portion 122a is out of the cam portion 49 (see Figs. 43, 45, and 46). A lock lever 124 is attached to the shaft portion 59 of the key rotor 51 so as to be unreleasable by the E ring 66. A fitting hole 125 of the lock lever 124 which is fitted with the shaft portion 59 is formed into a circular member so as to correspond to the shaft portion 59. In addition, a retaining piece 126 is formed on the lock lever 124 so as to face downward. As shown in Fig. 42, a coupling member 127 includes a fitting rectangular cylinder portion 128 and axially extending retaining projection 129 and engagement projection 130 integrally. The fitting cylinder portion 128 is movably fitted with the retaining piece 126. The retaining projection 129 is inserted into the retaining groove 123 of the moving member 122. The engagement projection 130 is engaged with the coupling member engagement recess 121 of the key rotor 51. The coupling member 127 is movable in the radial directions between the engagement position at which the engagement projection 130 is engaged with the coupling member engagement recess 121 as shown in Figs. 38 and 39 and the disengagement position at which the engagement projection 130 is disengaged from the coupling member engagement recess 121 as shown in Figs. 43 and 44, so that the key rotor 51 and the lock lever 124 can be rotated integrally with each other with the engagement projection 130 engaged with the coupling member engagement recess 121. A mode of operation of the aforementioned construction will be described next. In the condition before the key is inserted, the ends of the respective tumblers 56, 57 are inserted into the tumbler engagement grooves 48, 48 of the sleeve 47 by the spring members 58. That is, the respective tumblers 56, 57 are readily engageable with the sleeve 47 in the rotational direction (see Fig. 45). Under this condition, the key rotor 51 and the sleeve 47 are rotatable integrally with each other. In addition, not only the moving member 122 is set to the coupling position, but also the coupling member 127 is set to the engagement position, and the engagement projection portion 130 of the coupling member 127 is engaged with the coupling member engagement recess 121 of the key rotor 51 (see Figs. 38 and 39), so that the key rotor 51 is readily engageable with the lock lever 124 through the coupling member 127. Therefore, the key rotor 51 and the lock lever 124 are rotatable integrally with each other. At this instance, the retaining groove 123 of the moving member 122 is in communication with the groove 45 of the rotor case 42 (see Fig. 41). In addition, the moving block 71 bridges between the sleeve 47 and the rotor case 42 while engaged with the original position engagement recess 46 of the rotor case 42. As a result of the engagement, the sleeve 47 is held in the original position. When the regular key 41 is inserted into the keyhole 53 under this condition, the respective tumblers 56, 57 are released from the tumbler engagement grooves 48, 48 and set in the tumbler setting grooves 54, 55. Thus, the key rotor 51 is made freely rotatable with respect to the sleeve 47. As a result, as the inserted regular key 41 is rotated, the key rotor 51 is rotated with respect to the sleeve 47 and hence the rotor case 42, which in turn rotates the lock lever 124 that is engaged with the key rotor 51 through the coupling member 127 integrally, thereby allowing the cylinder lock to be unlocked. At this instance, the range of rotation of the key rotor 51 and the lock lever 124 is regulated by the retaining projection 129 of the coupling member 127 being abutted against the retaining portions 45a, 45a of the rotor case 42. In addition, since the sleeve 47 does not rotate even if the key rotor 51, the coupling member 127, and the lock lever 124 are rotated within such range, the moving member 122 remains held in the coupling position. Further, if a key other than the regular key, e.g., a wrong key 75, is inserted into the keyhole 53 to forcibly rotate the key rotor 51 under the aforementioned pre-insertion condition, at least some of the tumblers 56, 57 are brought into engagement with the tumbler engagement groove 48. As a result, the key rotor 51 and the sleeve 47 are rotated integrally with each other (see Figs. 43 to 46). When the sleeve 47 rotates, the moving member 122 is moved to the uncoupling position, which is down, by the slopes of the cam portion 49 arranged in the sleeve 47 (see an arrow D1 in Figs. 43 and 45) and, in association therewith, the coupling member 127 is moved to the disengagement position, which is down (see the arrow D1 in Fig. 44), disengaging the engagement projection 130 of the coupling member 127 from the coupling member engagement recess 121 of the key rotor 51. Further, when the sleeve 47 is rotated with respect to the rotor case 42, the moving block 71 is moved toward the key rotor 51 by the slopes of the original position engagement recess 46 (see an arrow D2 in Figs. 45 and 46), which disengages the moving block 71 from the rotor case 42 and in turn engages the moving block 71 with the engagement recess 61 of the key rotor 51. Therefore, in this case, the key rotor 51 and the sleeve 47 rotate integrally with each other, but the lock lever 124 is not rotated. Thus, the cylinder lock is not unlocked. That is, even if the key rotor is forcibly rotated by a wrong key or the like, the key rotor 51 and the sleeve 47 only rotate idly, which neither unlocks the cylinder lock nor gives any damaging force to the components thereof, thereby excluding the possibility of the components being broken and allowing the cylinder lock to be used again. By the way, in the fourth embodiment also, when the wrong key 75 is released with the key rotor 51 and the sleeve 47 having been rotated to an arbitrary position from the original position, the key rotor 51 and the sleeve 47 may, in some cases, be out of the original position. In such a case, in a manner similar to that in the second embodiment, when the regular key 41 is inserted into the keyhole 53, the respective tumblers 56, 57 are moved so as to be set in the tumbler setting grooves 54, 55, so that the tumblers 56, 57 are disengaged from the sleeve 47. However, the moving block 71 is engaged so as to bridge between the sleeve 47 and the key rotor 51. Therefore, when the key rotor 51 is rotated by the regular key 41, the sleeve 47 is also rotated integrally with the key rotor 51. When the key rotor 51 and the sleeve 47 are rotated as far as to the original position, the first engagement portion 73 of the moving block 71 confronts the original position engagement recess 46 of the rotor case 42 and is thereby engaged therewith (see Figs. 40 and 41). As a result, the key rotor 51 and the sleeve 47 come to be held in the original position. The cylinder lock according to the fourth embodiment such as described above can provide not only advantages similar to those of the second embodiment, but also the following advantages. Since not only the retaining piece 126 of the lock lever 124 is fitted with the fitting cylinder portion 128 of the coupling member 127 but also the engagement projection 130 of the coupling member 127 is engaged with the coupling member engagement recess 121 of the key rotor 51, a sufficiently large margin is given for the engagement of the engagement projection 130 with the coupling member engagement recess 121 in the axial direction, which in turn ensures sufficient mechanical strength for these engagement portions. Incidentally, in the case of the second embodiment, the projection 68 arranged on the fitting hole 67 portion of the lock lever 65 is engaged with the lock lever engagement recess 60 arranged on the shaft portion 59 of the key rotor 51. Therefore, only a margin as much as the thickness of the lock lever 65 can be provided for the engagement of the projection 68 in the axial direction, which thus makes it difficult to ensure a sufficient strength of the projection 68. The cylinder locks according to the present invention are provided as only rotating the key rotor and the sleeve idly and not rotating the lock lever even if a key other than the regular key, a screwdriver, or the like is inserted thereinto to forcibly rotate the key rotor. Therefore, not only the cylinder locks cannot be unlocked, but also no damaging force is applied to the components thereof. Hence, the possibility of the components being broken is excluded and the cylinder locks can thereby be used again. In addition, the absence of axially moving members contributes to preventing the cylinder locks from growing in size in the axial direction. The cylinder lock according to the present invention is provided as holding the sleeve in the original position by arranging the moving block in the sleeve and allowing the moving block to be engaged with the original position engagement recess of the rotor case, and as rotating the sleeve and the key rotor integrally with each other by causing the moving block to be engaged with the key rotor if the sleeve and the key rotor are rotated by a wrong key or the like. Therefore, the rotation of the sleeve can be prohibited at the time of regularly unlocking and locking the cylinder lock. In addition, the position of the sleeve and the key rotor can be identified.

Claims: A cylinder lock comprising: a fixedly arranged rotor case (1), a sleeve (8) rotatably arranged inside the rotor case (1) and having tumbler engagement grooves (9) formed therein, a key rotor (13) rotatably arranged inside the sleeve (8) and having an axially extending keyhole (14) and radially extending tumbler setting grooves (15) formed thereon, tumblers (16) movably arranged in the tumbler setting grooves (15) of the key rotor (13), the tumblers (16) being engageable with the sleeve (8) with ends thereof being held while inserted into the tumbler engagement grooves (9) by spring members (17) before a key is inserted, and being released from the tumbler engagement grooves (9) by insertion of a regular key, a lock lever (24) arranged so as to be selectively rotatable with the key rotor (13), and main coupling means for selectively coupling and uncoupling the key rotor (13) and the lock lever (24), characterized by a rear rotor (20) rotatably arranged so as to confront the key rotor (13) axially, a key rotor coupling portion (19) formed at a rear portion of the key rotor (13) confronting the rear rotor, a rear rotor coupling portion (21) formed at a front portion of the rear rotor (20) confronting the key rotor (13), and a coupling member (34) constituting a part of said main coupling means, selectively rotatably connecting the key rotor coupling portion (19) and the rear rotor coupling portion (21) and being arranged so as to be radially displaceable between coupling and uncoupling positions, the key rotor (13) and the rear rotor (20) being rotatable integrally together when the coupling member (34) is in its coupling position and the key rotor (13) being free to rotate independently of the rear rotor (20) when the coupling member (34) is in its uncoupling position, the coupling member (34) being located in said coupling position before insertion of a key, and by an uncoupling mechanism constituting a further part of said main coupling means, a moving element (27) of which uncoupling means being guided by the rotor case so as to be radially displaceable between an engagement position and a disengagement position, said uncoupling means being in its engagement position before insertion of a key and being displaceable into the disengagement position upon rotation relative to the rotor case (1) of the sleeve (8) whenever rotated by the key rotor (13) in the absence of a correct key, so that when the moving element (27) is in its disengagement position the coupling member is in its uncoupling position. A cylinder lock comprising: a fixedly arranged rotor case (42), a sleeve (47) rotatably arranged inside the rotor case (42) and having tumbler engagement grooves (48) formed therein, a key rotor (51) rotatably arranged inside the sleeve (47) and having an axially extending keyhole (53) and radially extending tumbler setting grooves (54,55) formed thereon, tumblers (56,57) movably arranged in the tumbler setting grooves (54,55) of the key rotor (51), the tumblers (56,57) being engageable with the sleeve (47) with ends thereof being held while inserted into the tumbler engagement groove (48) by spring members (58) before a key is inserted, and being released from the tumbler engagement groove (48) by insertion of a regular key (41), a lock lever (65) arranged so as to be selectively rotatable with the key rotor (51), and main coupling means for selectively coupling and uncoupling the key rotor (51) and the lock lever (65), characterized by the lock lever (65) being arranged at a rear portion of the key rotor (51) so as to be movable radially between an engagement position in which the lock lever (65) is so engaged with the key rotor (51) as to be rotatable integrally therewith and a disengagement position in which the key rotor is disengaged from the lock lever for free rotation independently thereof, a moving member (62) being slidably received in the rotor case (42) and operationally linked to the lock lever (65) so that when the moving member is radially displaced into a coupling position or an uncoupling position the lock lever correspondingly assumes its engagement or its disengagement position, the main coupling means also including a cam portion (49) arranged in the sleeve (47), the moving member (62) engaging the cam portion (49) such that before insertion of a key the moving member is set to its coupling position in which it remains unless the sleeve (47) should rotate relative to the rotor case (42) and that upon such relative rotation when the key rotor is rotated in the absence of a correct key the moving member (62) is displaced into its uncoupling position, so that the key rotor (51) then rotates independently of the lock lever (65). A cylinder lock comprising: a fixedly arranged rotor case (81), a sleeve (82) rotatably arranged inside the rotor case (81) and having tumbler engagement grooves (89) formed therein, a key rotor (83) rotatably arranged inside the sleeve (82) and having an axially extending keyhole and radially extending tumbler setting grooves (91) formed thereon, tumblers (92) movably arranged in the tumbler setting grooves (91) of the key rotor (83), the tumblers (92) being engageable with the sleeve (82) with ends thereof being held while inserted into the tumbler engagement grooves (89) by spring members before a key is inserted, and being released from the tumbler engagement grooves (89) by insertion of a regular key (114), a lock lever (98) arranged so as to be selectively rotatable with the key rotor (83), and main coupling means for selectively coupling and uncoupling the key rotor (83) and the lock lever (98), characterized in that the lock lever (98) is arranged at a rear portion of the key rotor (83) so as to be movable radially between an engagement position in which the lock lever (98) is engaged with the key rotor (83) to be rotatable integrally therewith and a disengagement position in which the lock lever is disengaged from the key rotor, a rear rotor (93) as part of said main coupling means being arranged in a rear portion of the key rotor (83) so as to be rotatable integrally with the key rotor and arranged so as to be movable with respect to the key rotor radially between a coupling position and an uncoupling position, to cause the lock lever (98) to move to the engagement position when the rear rotor (93) is in the coupling position and to cause the lock lever (98) to move to the disengagement position when the rear rotor (93) is in the uncoupling position, so that in the disengagement position the key rotor (83) is freely rotatable independently of the lock lever and the rear rotor is rotatable with respect to the lock lever, and a cam portion (96) as further part of said main coupling means being arranged in a rear portion of the sleeve (82), causing the rear rotor (93) to set to the uncoupling position before the key is inserted and to cause the rear rotor to move to the coupling position when the key rotor is rotated with respect to the sleeve (82). A cylinder lock comprising: a fixedly arranged rotor case (42), a sleeve (47) rotatably arranged inside the rotor case (42) and having tumbler engagement grooves (48) formed therein, a key rotor (51) rotatably arranged inside the sleeve (47) and having an axially extending keyhole (53) and radially extending tumbler setting grooves (54,55) formed thereon, tumblers (56,57) movably arranged in the tumbler setting grooves (54,55) of the key rotor (51), the tumblers (56,57) being engageable with the sleeve (47) with ends thereof being held while inserted into the tumbler engagement grooves (48) by spring members (58) before a key is inserted, and being released from the tumbler engagement grooves (48) by insertion of a regular key (41), a lock lever (124) arranged so as to be selectively rotatable with the key rotor (51), and main coupling means for selectively coupling and uncoupling the key rotor (51) and the lock lever (124), characterized by a lock lever (124) being arranged at a rear portion of the key rotor (51), a coupling member (127) as part of said main coupling means being mounted for rotation together with the lock lever (124) so as to be movable radially between an engagement position in which the coupling member (127) is engaged with the key rotor (51) to be rotatable integrally therewith and a disengagement position in which the coupling member is disengaged from the key rotor, said lock lever (124) therefore being rotatable integrally with the key rotor (51) when the coupling member (127) is in the engagement position, a moving member (122) as a further part of said main coupling means being arranged in the rotor case for radial sliding movement therein between a coupling position and an uncoupling position to cause the coupling member (127) to move into the engagement position while allowing the coupling member to rotate when the moving member (122) is in the coupling position, and to cause the coupling member (127) to move into the disengagement position while restricting the rotation of the coupling member when the moving member (122) is in the uncoupling position, so that the key rotor (51) is freely rotatable independently of the coupling member (127) and the lock lever (124), and a cam portion (49) being formed as a further part of said main coupling means on the sleeve (47) so as to act on the moving member (122) to cause it to move to the uncoupling position whenever the sleeve (47) rotates together with the key rotor.

Inventors: KITO SHOZO, OYABU YOSHINOBU, KITO, SHOZO, OYABU, YOSHINOBU, KITO, SHOZO, C/O KABUSHIKI KAISHA TOKAI, OYABU, YOSHINOBU, C/O KABUSHIKI KAISHA TOKAI
Applicants: TOKAI RIKA CO LTD, KABUSHIKI KAISHA TOKAI RIKA DENKI SEISAKUSHO
Application year: 1994
Main classification: E05B17
IPC codes: E05B29, E05B17